Wireless communications devices are an integral part of society and permeate daily life. The typical wireless communications device includes an antenna, and a transceiver coupled to the antenna. The transceiver and the antenna cooperate to transmit and receive communications signals.
A typical radio frequency (RF) transceiver includes a power amplifier for amplifying low amplitude signals for transmission via the antenna. Given that most mobile communications devices operate on limited battery power, energy efficient power amplifiers may be desirable. More specifically and as will be appreciated by those skilled in the art, Class C and E power amplifiers are common in mobile communications devices since they are efficient power amplifiers. These classes of power amplifiers are more efficient than Class A or B amplifiers, for example, but are subject to performance tradeoffs. For example, they may be nonlinear over certain frequencies and may introduce greater amounts of distortion into the amplified signal (if the signal requires a linear amplifier).
In some communications applications, two or more smaller power amplifiers may be combined to provide a cumulative output without the incumbent complexity of a larger device. In other applications, a single amplifier may not be able to provide the needed performance in a practical implementation. This combination of two smaller amplifiers may be provided with a power RF combiner circuit. The “Wilkinson” type combiner is a typical RF combiner circuit with a number of input ports, for example, as disclosed in U.S. Pat. No. 3,091,743 to Wilkinson. The “Wilkinson” type power combiner may obtain input port-to-port isolation for each port by feeding each of the other ports with the signal applied to any one port through resistors with a 180 degree phase shifted voltage, with one-quarter wavelength transmission lines providing the 180 degree phase shift required for cancellation. For high frequency (HF) applications, i.e. 2 to 30 MHz, the physical length of the one-quarter wavelength transmission lines becomes impractical for many applications.
An approach to this drawback of “Wilkinson” type power combiners in HF applications may include using ferrite transformers instead of the one-quarter wavelength transmission lines, for example, as disclosed in U.S. Pat. No. 3,428,920 to Oleksiak. Referring to FIGS. 1-2, another such power combiner 20 is shown. This wound-wire type toroidal power combiner 20 illustratively includes a circuit board 23, a 100-Ohm bridging resistor 24 installed on the circuit board for dissipating any power mismatch in input power supplies 31-32 (50-Ohm input impedance), and three toroidal transformers 25a-25c installed on the circuit board and defining a power combiner circuit. Each toroidal transformer 25a-25c illustratively includes a ferrite core 22a-22c and Teflon coated windings 21a-21c surrounding the respective ferrite core. The wound-wire type power combiner 20 illustratively includes a 50-Ohm load resistor 27 coupled to the toroidal transformer 25c. 
As will be appreciated by those skilled in the art, the Teflon coated windings 21a-21c are typically hand wound through the ferrite cores 22a-22c and are used for their desirable high breakdown voltage properties. Moreover, Teflon coated windings may be costly. This makes the manufacturer of such HF power combiners time consuming and expensive.